DC converter valves are core devices for DC transmission. A converter valve usually includes a plurality of components. The components of the converter valve include a thyristor assembly, an anode reactor, etc. The thyristor assembly further includes a thyristor, a radiator, a damping resistor, a damping capacitor, and an associated cooling system. The converter valve has a complex structure and includes many parts. The converter valve may suffer from failures due to various reasons during operation, and needs to be repaired in time if failure occurs, so as to resume its normal operation. Therefore, the convenience of device maintenance needs to be considered at various stages in the design process of the converter valve.
Currently, there are primarily two forms of damping resistors for a thyristor assembly. In the first form, the damping resistor is a water resistor, and the damping resistor is in direct contact with cooling water, dissipates heat independently, and has nothing to do with the thyristor radiator and cooling water pipeline thereof. When the cooling system operates normally, the damping resistor can dissipate heat well. However, if the damping resistor is faulty and needs maintenance, the cooling water inside the converter valve has to be discharged completely before the maintenance can be done. As a result, the maintenance is difficult and time consuming. In the second form, the damping resistor is a rod resistor. A plurality of rod resistors are disposed inside through holes provided beforehand in the thyristor radiator, and the damping resistors dissipate heat indirectly via the thyristor radiator, reducing the number of joints inside the converter valve assembly. However, some rod resistors may interfere with the cooling water pipeline of the thyristor radiator. As a result, when a rod resistor interfering with the cooling water pipeline is to be maintained, cooling water in the converter valve still needs to be discharged completely before the cooling water pipeline can be disassembled, leading to difficult maintenance.